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<html lang="en">
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    <meta charset="UTF-8">
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    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
</head>
<body>
    <script>
        function quchong(arr){
            var newarr =[];
            for(var i = 0;i<arr.length;i++){
                if(newarr.indexOf(arr[i]) === -1){
                    newarr.push(arr[i]);
                }
            }
            return newarr;
        }
            var demo = quchong(['a','f','g','e','a','g'])
            console.log(demo);
    </script>
</body>
</html>